Method of making partial oxidation products



June 29, 1937. J. H. JAMES METHOD OF MAKING PARTIAL OXIDATION PRODUCTSOriginal Filed Jan. 22

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R m N w m Q Q 3 Q a S m v N n w Patented June 29, 1937 UNITED STATESPATENT OFFICE METHOD OF MAKING PARTIAL OXIDATION PRODUCTS Joseph HidyJames,

Pittsburgh, Pa., assignor to Clarence P. Byrnes, trustee, Sewickley, Pa.

11 Claims. (01. 260 -116) My invention relates to the manufacture ofintermediate oxidation products such as aldehyde fatty acids, frommineral oils or hydrocarbons or. their products or derivatives, whether5 liquids or gases either alone or in mixture. Where mineral oil isused, it is preferably one of the distillates of crude mineral oil(petroleum), although the process may be applied to crude oil, or oilsfrom shales or their distillates, or oils from low-temperaturedistillation of lignites or coals or other distillates.

It has heretofore been proposed to spray a mineral oil distillate into acurrent of air mixed with steam, this mixture being passed over as-Ilzzestos coated with finely divided copper oxide ept of the mixture. Noattention was paid to the air ratio. In such a laboratory experiment asmall proportion of an unknown organic acid was found in the condensedproduct; but the hydrocarbon used was largely consumed in keeping thecatalyst layer at a red heat. Such process cannot be carried out on apractical or commercial scale as the yield is too small, the productimpure,

and the hydrocarbon mainly consumed.

I have discovered that by vaporizing such oils, forming a heated mixtureof the oil vapor with a proper proportion of air, either with or withoutsteam, and passing the heated mixture through a suitable catalyst layerwhile keeping the reaction below that of continuous self-sustainedcombustion, I can produce in commercial quantities a mixture of valuableintermediate oxidation products, including aldehyde fatty acids; and canhold the reaction temperature within the proper range therefor bymaintaining proper conditions.

In such process, while heat is continuously supplied to vaporize theoil, and, if necessary, additional heat is supplied to bring the mixtureto the reacting temperature especially in starting;

yet the catalyst is kept below a red heat and preferably below a heatwhere it shows any glow, to prevent continuous self-sustained combustionwhich will consume a large amount of the hydrocarbon. The heat mightrise temporarily to a point of ignition but in such case the yield isreduced; and the air and vapor ratio should be changed to prevent suchcombustion continuing. In my process there is a partial oxidation orpartial combustion of the mixture within the proper range hereinafterset forth, producing intermediate combustion products including aldehydefatty acids.

If steam is added, it will serve as a diluent to hold down the reactionzone temperature and it will aid in vaporizing heavier oils. The steamshould be carefully regulated, since excess will lower the acid yield.

By long experimenting I have found that a number of inter-dependentvariable conditions or factors, dependent on each other, are importantin obtaining proper yields. Thus the proportion of air, the particularcatalyst used, the Velocity of the current and the temperaturemaintained in the reaction zone are inter-dependent and should beaccordingly varied in relation to each other. The thickness of catalystis also a factor.

Heat should be continuously supplied to vaporize the oil and topreferably give an additional amount of heat, but the air ratio shouldbe maintained, preferably above the theoretical amount; at such a ratethat continuous self-sustained combustion does not occur, or steam, ifit is used, can be supplied for this purpose. The reaction gives outheat and the temperature must be held down in the conversion zone. Theheat may be supplied to vaporize the oil and, particularly, in starting,heat may be supplied to the catalyst by an electric resistance orotherwise, as desired.

In making aldehyde fatty acids the temperature in the conversion zoneshould be maintained above that at which there is a predominance ofaldehydes, but below that of self-sustained combustion; although someother intermediate conbustion products including aldehydes are producedin forming aldehyde fatty acids. In making a predominance of aldehydesthe temperature is somewhat lower than for acids.

3 The range of temperature for carrying out my invention and obtaininguseful partial combustion products extends, so far as I have determined,from about 230 degrees C. up to about 450 degrees 0., the temperatureused will depend on the hydrocarbon being treated, from heavy gasolineto the heaviest hydrocarbons that can be vaporized; and also depends onthe catalytic material used, the proportion of air employed whether ornot steam is added, and, to some extent, on the speed of the currentmixture. I have found that the lighter the hydrocarbon treated, thehigher the reaction zone temperature should be maintained, and whenheavier distillates are used lower temperatures may be employed.Generally speaking for producing a predominance of aldehyde fatty acids,the upper portion of the above temperature and range is used. It will beunderstood, however, that I am speaking merely of predominance ofpercentages in the product, since in making air can approach thetheoretical amount.

. aoeaaai I aldehyde fatty acids, some proportion of aldehyde is formedand vice versa.

The. catalysts hereinafter described differ in activity. With an activecatalyst kept at the highest temperature consistent with a highcommercial yield product, the proportion of air should be kept at orabove that required by theory, the temperature, of course, being keptbelow that where products of complete combustion, namely, carbonicdioxide and water, form to a large extent. With more active catalysts ahigher speed may be used, especially where a higher temperature withinthe desirable range is employed.

The time of contact with the catalyst may be lessened with the moreactive catalyst and with a higher temperature. With hydrocarbons ofgreater molecular weight, more heat must be applied to vaporize them,but the reaction zone heat should be lower. With oils of lower or lessmolecular weight, less heat will vaporize, but the temperature of thereaction zone should be higher. The same temperature range may, however,be used on two successive distillates with good yields. With fractionsof widely different molecular weight, the difference in reaction zonetemperature is marked.

The desired temperature in the reaction zone can be kept down below aglowing temperature by lowering the proportion of air nearer thetheoretical amount as the temperature rises, and by raising theproportion of air as the temperature decreases, within certain limits.The more active the catalyst, or the higher the temperature within thedesired range, the nearer the proportion of With less active catalysts,or with lower temperature, the greater should be the proportion of air.

The products after leaving the reaction zone are chilled and condensedor absorbed for recovering them.

As regards the catalyst employed, I prefer the complex oxides orcompounds of metals having a varying valence. All parts of the complexmay consist of oxides of the same metal or of different metals. Forexample, an excellent catalyst in this connection consists of theso-called blue oxides of molybdenum, which contain molybdenylmolybdenate, and molybdenyl molybdenite, and are probably all chemicalcompounds of two or more oxides of molybdenum representing differentstates of oxidation. These complexes may be regarded as salts; that is,compounds of one or more basic with one or more acid oxides.

Other complexes of value for such catalysts are chromic chromate, uranyluranate, tungsten tungstate, the manganese complexes, the vanadiumcomplexes, etc.

The basic and acid parts of these complexes may be formed from oxides ofdifferent metals, in which case, each metal, or group of metals used,should possessvarying valence. Examples of this class are:

Cobalt molybdate CeOMoOa Cobalt molybdite CeOMoOn Di-uranyl vanadate(UrOz) 2V205 etc.

Those metals, whose complexes I prefer to employ as the acid part of thecatalyst, (since I have found them to be of high activity in thisfield), are the metals of high melting point electronegativelow-atomic-volume metals having an atomic weight above 40. These metalsappear on the Lothar-Meyer diagram of the periodic series beginning onthe descending side of the third peak,

tantalum, tungsten and uranium. The basic oxides may be the. loweroxides of these metals or may be the oxides of iron, copper, nickel,lanthanum, cobalt, thorium and the eight or nine rare earth metals.

In both acid or basic portions there may, of course, be two or more ofthese combined.

With the above description of the conditions, which are varied to givethe best commercial results according to ,the interaction of the factorsdescribed, I will now describe one form of apparatus for carrying out myinvention.

In the drawing, 2 represents a valved air pipe through which air issupplied under pressure, 3 a meter for the air, and 4 the pipe leadingfrom the meter into a heating and mixing vessel 5. 6 represents a vesselcontaining liquid hydrocarbon and 'l a valved pipe leading therefrominto the mixing vessel 5. 8 indicates a burner having a valved supplypipe 9, by which the heat may be regulated. It) represents the walls of,the furnace or heating chamber in which the retort or mixing vessel 5 isset, the heated mixture of hydrocarbon vapor and air passing from themixing vessel through the channel H to the catalytic layer 12. Thiscatalytic layer is shown as having a frame l2a, clamped or beltedbetween the ends of the channel I l and the flanged end of the conduitl3, leading to a vertical condenser I4. The products emerging from thecatalytic layer pass down through thetubes l5 of the condenser into thevessel l6. l1 represents the valved inlet pipe for water passing intothe condenser, and IS the outlet pipe for the circulating water. Thevessel I6 is provided with an outlet l9 for fumes, 20 being the valvedpipe by which the condenser products are drawn off. Between thecondenser and the vessel l6 and the furnace, I preferably provide aninsulating screen 2|, of some heat insulator to keep the heat of thefurnace away from the condensing apparatus.

22 represents a pyrometer which may be in the form of an electric couplewith its wires 23 leading to an external temperature indicator 24.

As the heated mixture of vapor and air in the proper proportions passesthrough the catalytic layer under the regulated conditions referred to,partial oxidation or partial combustion takes place, the products beingimmediately taken to and through the condenser, and the desired productcollecting in the vessel succeeding the condenser. The condensingapparatus may of course be of any desirable type, either in single ormultiple form. I may in some cases lead pipe l9 to a scrubbing system torecover any uncondensed products.

I will now describe some specific examples of my process.

(1) Using as a catalyst blue oxides of molybdenum, the coated asbestoslayer being one centimeter thick and 4.4 centimeter diameter. The oilused was a gas oil fraction distilling from 250 to 295 degrees C. Theair rate was two liters per minute or 1.6 times the theoretical amountrequired for aldehyde fatty acid formation. The absorbers consisted ofeight water bubblers. The oil was fed at the rate of 126 cubiccentimeters per hour. The time of contact with the catalyst was .32second; temperature of the catalyst was maintained at about 2'70 degreesC. duration of the run was one hour and 35 minutes. A test of the exitgas showed 2.4% of carbon dioxide and 1% of oxygen. 150 cubiccentimeters of liquid oxidation products were recovered, of

which about 45% by volume consisted of aldehyde fatty acids, and about55% by volume of alcohols, unchanged hydrocarbons, and undeterminedproducts.

(2) The catalyst consisted of uranyl uranate and uranyl uranite onasbestos, 1.25 centimeters thick and 4.4 centimeters in diameter. Theoil used was kerosene distilling at 250 to 295 degrees C. The air ratewas 4 liters per minute, the condensing and absorbing system consistingof two Worm condensers and four water bubblers. The oil was entered atthe rate of 200 cubic centimeters per hour. The time of contact wasabout .33 second. The temperature of the catalyst was maintained atabout 310 degrees C. Duration of the run33 minutes. As a result 76 cubiccentimeters of liquid product were recovered, which, on analysis, gavealdehyde fatty acids about 30% and aldehydes, etc., about 70%.

This run was made to show the temperature effect, the'temperature beinglower than that propr for the other interdependent conditions.

In the next test, I established a more nearly correct temperature asfollows:

(3) The conditions were all the same as with the second run, except thatthe temperature of the catalyst was maintained at about 420 degrees C.As a result of this test, 70 cubic centimeters-of liquid product wererecovered which gave the following analysis: aldehyde fatty acids 42.5%aldehydes 33.70% and hydrocarbons, etc., 23.75%.

To show the effect of increasing the proportion of air in the mixture, Iran another test substantially like No. 1, above recited, except thatthe air was fed at the rate of about 10 liters per minute or 66 timesthe theoretical amount required for fatty acid formation. In this case,the oil feed was 15 centimeters per hour; the time of contact with thecatalyst about .03 second; and the duration of the run about 3 hr. 20min., the temperature of the catalyst being 260 to 280 degrees C. Inthis case, .756 gram of a dark tacky resinous acid mixture wasrecovered,

amounting to about 18% by weight of the weight of hydrocarbon treated.This shows the effect of too high a ratio of air under the conditionsnamed.

With an apparatus for larger scale operation, practically identical withthat figure in the drawing accompanying this specification, thefollowing run was made:

Conditions (a) Catalyst: blue oxides of molybdenum on asbestos, heldbetween parallel wire mesh screens as shown in figure, the activematerial packed in the disk-shaped space 15 inches in diameter and of aninch thick.

(5) Hydrocarbon mixture treated: mineral seal oil, a Pennsylvaniapetroleum distillate, 90% of which distilled between 250 and 324 degreesC. The distillate had a specific gravity of .8125 at 20 degrees C.

(a) Air rate: about 216 cubic feet per hour.

(d) Absorbing system: no scrubbers, only the parallel tube condenser asshown in figure.

(6) Oil feed: 2.5 gallons per hour.

(1) Time of contact of h. c. vapor-air mixture with catalyst;approximately .3 second.

(9) Temperature of catalyst: 310 to 320 degrees C. D

(h) Total time consumed in run: 2 hours.

Results (a) Carbon dioxide analysis (by volume) in exit gas streamduring rur (.6%, 1.0%, .8%).

Carbon monoxide analysis .oy volume) in exit gas stream during run:(6.8%, 8.%).

(b) 3.7 gallons of product (having specific gravity at 20 degrees C. of.852) were recovered which had the following analysis; aldehyde fattyacids, 46% by volume, aldehyde 28%, leaving undetermined 26% by volume.

Actual recovery of aldehyde acids, by weight, based on weight ofhydrocarbon mixture treated: 50.7%.

The above examples in connection with the description of the apparatusand operation will sufficiently disclose to those skilled in chemistrythe essentials of the process, under the conditions recited above.

I believe that the aldehyde fatty acids are formed in stages, passingthrough intermediate stages to the desired stage. With a lowertemperature and other factors suitably changed a predominance of loweroxidation products, such.

as aldehydes may be produced. The aldehyde acid stage seems to be astable one and soaps may be made therefrom by saponifying in the usualmanner, I

So far as I have found, the lowest reacting temperature for successfulcommercial operation can be used when the catalyzer consists of theintermediate complex compounds of oxides of molybdenum. The next lowesttemperature has been used with catalysts consisting of the compounds ofmolybdenum with other metallic oxides of the group above named.

While a catalytic layer is important, if not essential, in obtainingcommercial yields, I have found that a non-catalytic screen may be used.Even a plain tube may be used with suflicient heat supplied to it togive the desired reaction while preventing continuous self-sustainedcombustion. When the factors are properly arranged in such case as aboverecited, I have found that We can obtain a low yield of say 10 to 20% ofthe aldehyde fatty acids by passing the mixture through a tube, the zoneof which is kept heated to a point which will give a desired reactionwithout causing continuous self-sustained combustion. A heated metallicscreen may be used instead of heating the walls of the tube; but suchprocesses give a relatively low yield as compared with the use of mypreferred catalysts.

I consider myself to be the first to discover a practicable process ofpartial oxidation whereby mineral oils and their distillates may bepractically and commercially converted into intermediate oxidationproducts in the range from alcohols to aldehyde fatty acids; and thefirst to discover the inter-relation, inter-dependence and properproportions of the factors above named, to give the desired result.

The advantages of my invention will be apparent to chemists since apracticable method is afforded by which aldehyde fatty acids may beobtained in commercial quantities at a low cost. Aldehydes and otheroxidation products may also be produced in commercial quantities bylowering the temperature somewhat. For example, in cases 1 and 3, bylowering the temperature of the catalytic mass to about 230 to 250degrees C., for 1, and to 280 to 290 degrees C., for 3.

If distillates, solid at ordinary temperatures, are used, I may liquefythese hydrocarbons: by heat and then vaporize them in the process. Bythe terms aldehyde fatty acids and aldehyde acids herein I intend toinclude such forms of oxygenated organic acids as are produced by my thebroader claims and that species wherein the acids predominate, whatevertheir form or character.

By the term "air" in my claims, I intend to cover air or oxygen or anygas containing oxygen.

Many changes may be made in the form of the apparatus employed and thecatalyst used, and the important factors named may be varied within thelimits above described, without departing from my invention.

By the words mineral oil in the claims, I intend to cover crude mineraloil or shale oil, or their distillates, preferably the heavier andcheaper distillates, or the products of low-temperature distillation oflignites or coals, these being generally termed aliphatic hydrocarbonsof both. the saturated and unsaturated type. I do not intend to coverherein any partial combustion process relating essentially to oxidizingthe class of arcmatic hydrocarbons. By the term compound in my claimsrelating to the catalytic material, I intend to cover either salts,compounds or oxides.

The majority of the claims to the subject matter disclosed herein arepresent in my Reissue Patent No. 18,522, reissued July 12, 1932(original Patent 1,697,653 of January 1, 1929, being a continuation ofthis application).

I claim:

1. The process of treating hydrocarbons which comprises passing amixture of the hydrocarbon and air over a heated catalyzer andwithdrawing the products prior to complete utilization of the oxygen inoxidizing reactions.

2. In the catalytic oxidation of petroleum .hydrocarbons the step whichcomprises passing the reaction mixture over a catalytic mass of highheat conductivity maintained at a black heat approaching a low red heat.

3. In the catalytic oxidation of petroleum hydrocarbons the step whichcomprises passing the reaction mixture over a catalytic mass ofsubstantially the heat conductivity of metallic masses and maintainingthe temperature at a black heat approaching a low red heat.

4. In the catalytic oxidation of petroleum. oils the step whichcomprises passing a mixture of petroleum vapor and air over a compositecatalyzer containing two active oxidizing agents, said catalyzer havingsubstantially the heat conductivity of metallic masses.

5. The process of treating hydrocarbons which comprises passingpetroleum vapors admixed with air through a conversion zone heated to atemperature within the range of partial oxidation and within atemperature range at which the very heat-sensitive products of oxidationare substantially retained in the materials withdrawn from theconversion zone;

6. The process of oxidizing kerosene which comprises vaporizing thisoil,passing it in admixture =with heated air into contact with a porouscatalytic mass heated to an oxidizing temperature and extractingwater-soluble organic acids from the products of oxidation.

- 7. The process which comprises heating a mineral oil fraction toproduce' vapor thereof, ad-

mixing the vapor with a gas containing free ture in contact with acatalyst, but at a temperature below that of continuous sustainedcomplete combustion.

9. In the manufacture of partial oxidation products, the stepscomprising feeding a preheated gaseous phase mixture of aliphatichydrocarbon and a gas containing free oxygen through a reaction zone atan elevated temperature below that of continuous self-sustained completecombustion-and within the range where partial oxidation products areproduced, and recovering products from the exit stream beyond said zoneof reaction.

10. In the manufacture of partial oxidation products, the stepscomprising feeding a preheated gaseous phase mixture of aliphatichydrocarbon and a gas containing free oxygen through a reaction zone incontact with a catalyst at an elevated temperature below that ofcontinuous self-sustained complete combustion and within the range wherepartial oxidation products are produced, and recovering products fromthe exit stream beyond said zone of reaction.

11. In the manufacture of partial oxidation products, the stepsconsisting of preheating a gaseous phase mixture of aliphatichydrocarbon and a gas containing free oxygen, feeding said preheatedmixture through a reaction zone at an elevated temperature below that ofcontinuous self-sustained complete combustion and within the rangewherein partial oxidation products in the range from alcohols to organicacids are produced, and recovering such products from the exit streambeyond the zone of reaction.

JOSEPH HIDY JAMES.

